Regensburg 2025 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 50: Superconducting Electronics: SQUIDs, Qubits, Circuit QED II
TT 50.7: Vortrag
Donnerstag, 20. März 2025, 16:45–17:00, H36
Heat transport in the quantum Rabi model: Universality and ultrastrong coupling effects — Luca Magazzu1, Elisabetta Paladino2,3, and •Milena Grifoni1 — 1University of Regensburg — 2Università di Catania, Italy — 3INFN, Sez. Catania, Italy
Heat transport in a qubit-oscillator junction weakly coupled to heat baths displays a rich variety of effects depending on the junction parameters. Signatures of the transition to the regime of ultrastrong qubit-oscillator coupling appear in the thermal conductance, current, and rectification. For example, upon increasing the coupling, the conductance as a function of a bias applied to the qubit undergoes a transition from a resonant to a broadened, zero-bias peak behavior. At low temperatures, coherent heat transfer via virtual processes yields a universal power-law behavior in the linear conductance as a function of the temperature. In addition, the low-temperature conductance is modulated by a prefactor which unravels the multilevel nature of the junction: A coherent suppression arises in the presence of quasi-degeneracies in the spectrum. At higher temperatures, sequential processes dominate heat transfer and a scaling regime is found when quantities are scaled with a coupling-dependent Kondo-like temperature.
[1] L.Magazzù, E.Paladino, M.Grifoni, Phys.Rev.B110, 085419 (2024);
[2] L.Magazzù, E.Paladino, M.Grifoni, arXiv:2403.06909 (2024).
Keywords: Heat transfer; Open quantum systems; Quantum interference effects; Quantum master equation; Diagrammatic methods